In the early 1950s, a plastic surgeon named Maxwell Maltz began noticing an unusual tendency among his patients.
When Dr. Maltz would perform an operation — like a nose job, for example — he found that it would take the patient about 21 days to get used to seeing their new face. Just like that, he noticed that when a patient would suffer from arm or leg amputation, the patient would still sense a phantom limb for about 21 days before adjusting to the new situation.
These experiences prompted Maltz to think about his own adjustment period to changes and new behaviors, and he noticed that it also took himself about 21 days to form a new habit. Maltz wrote about these experiences and said, “These, and many other commonly observed phenomena brought him to the conclusion that it takes about a minimum of 21 days for a previous mental image to dissolve and add a new one to jell.”
In 1960, Maltz published that quote and his other thoughts on behavior change in a book called Psycho-Cybernetics (audiobook). The book proved out to be a medical bestseller hit, selling more than 30 million copies.
And that’s when the problem started.
Maltz’s work influenced nearly every major “self-help” professional in the decades that followed be it Zig Ziglar or Brian Tracy or Tony Robbins. More and more people were talking about this now, reciting the story to one another and it was spreading like a fire in the jungle, people began to forget that he specifically stated that “a minimum of about 21 days” not the shortened version that they produced out of it which said, “It takes 21 days to form a new habit.”
Soon this misinformation took the image of a proven fact that it takes 21 days to form a new habit (or 30 days or some other magic number) since people were transferring this myth from one to another. The number of times these timelines are quoted as statistical facts is just remarkable. Dangerous lesson: If a large number of people say something a large number of times, then its common that everyone else will start believing them too.
How Long it Really Takes to Build a New Habit
Phillippa Lally is a health psychology researcher at University College London. In a study published in the European Journal of Social Psychology, Lally and her research team decided to figure out just how long it actually takes to form a habit.
The research program examined the habits of 92 people over a 12-week period. It started then like each of them would choose one new habit for the span of 12 weeks and will report it each day on whether or not they followed the new habit or missed it by any chance.
Some people were given simple tasks to dissolve into their daily habits like “drinking a glass of water with breakfast.” While the other half was given a bit more exhaustive task like “sprinting for straight 20 minutes before munching on the dinner.” At the end of the 12 weeks, the researchers analyzed the data to determine how long it took each person to go from starting a new behavior to automatically doing it.
It was observed that a new behavior becomes automatic in more than two months on an average — 66 days to be exact. And how long it takes a new habit to form can vary widely depending on the behavior, the person, and the circumstances. In Phillippa’s study, it took people about 18 to 254 days to form a new habit.
In other words, if you want to set your expectations appropriately, the truth is that it will probably take you anywhere from two months to eight months to build a new behavior into your life — not 21 days.
Where to Go From Here
At the end of the day, how long it takes to form a particular habit doesn’t really matter that much. Whether it takes 50 days or 500 days, you have to put in the work either way. If you want to get to the 500th day you have to start with the 1st day. So forget about the number and focus on doing the work.